Electrical relay



Oct. 2, 1934. H. cs. BLossER ELECTRICAL RELAY Filed Jan. 4, 1934 2 Sheets-Sheet l I 1. r I

11/ 1/ r, ri I111 INVENTOR Herman 0. Bl 0.51991 Hi6 ATTORNEY Oct. 2, 1934. BLOSSER 1,975,652

ELECTRICAL RELAY Filed Jan. 4, 1934 2 Sheets-Sheet 2 INVENTOR Herman G.B[OSSOP BY 4mm HIS ATTORNEY Patented Oct. 2, 1934 STATES Ars The Union Switch &

Signal Company, Swissvale, Pa, a corporation of Pennsylvania Application January 4,

L334; Serial No. 705,278

.7 Claims. (Cl. 20093) My invention relates to electrical relays and block 13, and a non-magnetic shim 18 similar" particularly to relays which are suitable for use as track or line relays in signaling systems employing for the control of the signaling devices direct current which is periodicallyinterrupted or coded at diiierent frequencies in accordance with difierent traflic conditions.

One object of my invention is to provide a sensitive relay of the type described which is capable of reliable operation at high speeds over long periods of time.

Another object of my invention is to provide a relay of the type described which is designed tobe operated on direct current of one polarity only, and which will not respond to direct current having a polarity opposite to that for which the relay is designed. I

Other objects of my invention will appear as the description proceeds.

In the accompanying drawings, Fig. 1 isa front elevational view showing one form of relay embodying my invention, certain of the parts being shown broken away or sectioned to better illustrate the construction. Fig. 2 is a side view of the relay shown in Fig. 1. Fig.3 is a sectional view taken on line III-III of Fig. 2.

Similar reference characters refer to similar parts in all three views.

Referring first to Figs. 1 and 2, the relay comprises a suitable case consisting of a top plate 1 of insulating material secured to the upper end of a substantially U shaped non-magnetic bracket 2, a metallic base plate 3 secured to the lower end of the bracket 2, and a transparent glass cylinder 4 clamped between the top plate 1 and the base plate 3. A gasket 5 of cork or other suitable material is interposed between the top plate 1 and the upper end of the cylinder 4, and a similar gasket 6 is interposed between the bottom plate and the lower end of the cylinder, thereby sealing the case against the entry of dust, and other foreign substances.

The operating mechanism of the relay is mounted on the U-shaped bracket 2, and as here shown, comprises a core structure consisting of two vertically disposed bars 7 and 7 secured, respectively, to the legs 2 and 2 of the bracket 2 by means of bolts and 10 The bars 7* and 7 are provided at their upper ends with adjustable pole pieces 8 and 8 having confronting pole faces 9 and 9 and clamped between the lower ends of these bars by means of a non-magnetic bolt 11 are .a non-magnetic shim 12, a magnetizable block 13, three magnetizable plates 14, 15 and 16, a magnetizable block 17 similar to the to the shim 12. The blocks 13 and 17, in addition to being clamped between the lower ends of the bars 7 and 7 are fastened to the web 2 of the bracket 2 by means of bolts 13 and 17 and it twill be apparent, therefore, that the core structure is securely fastened to the bracket.

Associated with the core structure is a permanent magnet 20 which, as here shown, is in the form of a rectangular bar. This magnet extendsparallel to the pole pieces 8 and 8 directly opposite these pole pieces, and is secured tothe bracket 2 by means of a channel shaped non-magnetic member 21 which fits over the outer edge of the magnet, and two non-magnetic bolts 22 and 22 which extend through holes in .the member 21 and are screwed into tapped holes provided in the legs of the bracket. The permanent magnet is magnetically connected with the core structure of the relay by means -ofchannel-shaped magnetic members 23- and 23 which are best seen in Fig. 3 and which are -interposed between the bars 7 and 7 of the core structure and the magnet.

-As best seen in Fig. l, the plate 15 of the core structure has its upper edge disposed below the upper edges of the adjacent plates 14 and 16 to provide a channel 24,'and loosely mounted to oscillate about its lower end as a fulcrum within this channel is a magnetizable armature 25. This armature projects upwardly through a hollow spool 26 upon which the operating winding 27 of the relay is wound, and cooperates adjacent its upper end with the pole pieces 8 and 8 of the core structure. Formed in the opposite edges of the armature just above the channel 24 are notches and 25 and projecting loosely through these notches are laterally extending fingers 14 and 14 formed on the upper end of the plate 14, whereby the armature is hinged to the core structure without the use of trunnions. In order to preclude the possibility of the armature coming into direct contact with the pole pieces, stop pins 28 of brass or other non-magnetic material are secured to the armature as shown. The leads 27 and 27 of the winding 27 extend upwardly and are secured at their upper ends to terminal posts 29 and 29 mounted on the top plate 1. Painted or otherwise formed on the top plate adjacent the terminal posts 29 and 29 respectively, are the symbols plus and minus (not shown) indicating the correct polarity of the current on which the relay is designed to be operated.

With the above described construction, it will be noted that a low reluctance path is provided between the armature and the magnetizable blocks 13 and 17, which blocks serve as fixed pole pieces. It will also be noted that the air gaps at the rearof the magnetic circuit, that is to say, the air gaps between the blocks 13 and 1'7 and the associated bars 'I and 7 are fixed and equal, while the working air gaps at the front of the magnetic circuit, that is to say, the air gaps between the armature and the pole pieces 8 and 8', may be adjusted by varying the positions of the pole pieces with respect to the associated bars.

The permanent magnet 20 is preferably made of cobalt steel because of its well known property of retaining a high degree of magnetic saturation over long periods of time, and the armature and magnetizable parts of the magnetic circuit are preferably made of 50% nickel steel because of the low coercivity of this material. The path of the polarizing flux through the core structure is from the right-hand end of the permanent magnet, as viewed in Fig. 1, through the upper end of the magnetizable bar 7*, at which point the flux divides into two paths. One of these paths passes downwardly through bar l -across the non-magnetic shim 12, through the magnetizable b1ock'13, the magnetizable plates 14, 15 and 16, and the magnetizable block 17, across the non-magnetic shim 18, and then upwardly through the bar 7 to the other end of the permanent magnet. The other path passes through the pole piece 8 the air gap between the pole piece 8 and the upper end of the armature, the upper end of the armature, the air gap between the upper endof the armature and pole piece 8, pole piece 8 and bar 7 to theleft-hand end of the permanent magnet as viewed in Fig. 1. Another path forthe polarizing flux which leaves pole piece 8 extends downwardly through the length of the armature 25, then through the block 17 andbar 7 to the left-hand end of the perinanentmagnet. Should the armature -25 occupy its other extreme position, some of the flux which leaves the right-hand end of the permanent magnet will 'pass' through bar 7 block 13, then upwardly through the armature 25, and pole piece 9 to the left-hand end of the permanent magnet.

It will be apparent, therefore, that both the amount and the direction of the polarizing flux which passes lengthwise through the armature depends upon the particular position of the armature with respect to the pole-pieces 8 and 8 When the armature is midway between these pole-pieces, there is no polarizing flux through the armature in the direction of its length because both ends of the armature are then at the same magnetic potential, but as the armature moves toward one or the other of the pole pieces, flux flows through the armature in one direction or the other depending upon which pole piece is approached.

The paths of the flux due to current flowing in the operating winding 2"! of the relay may be traced from the upper end of the armature where it divides between the air gaps to pole-pieces 8 and 8 thence through the bars I and 7 the non-magnetic shims 1 2 and 18, the magnetizable blocks 13 and 17, the magnetizable plates 14 and 16, and the magnetic plate 15 into the lower end of the armature. The direction of the flux in these paths depends, of course, upon the polarity of the current supplied to the operating winding 27, and it will be apparent that when this flux is in one direction, the armature will be repelled from the pole piece 8 and attracted to the pole piece 8 but with the current reversed and this flux in the opposite direction, the armature will then be repelled from the pole piece 8 and attracted to the pole piece 8*. There is also a third path for the operating flux, passing through the permanent magnet, but due to the fact that the magnetomotive force of the electromagnetic fiux is at about the same potential as that of the permanent magnet at the connecting points, and also due to the high reluctance of the permanent magnet as compared to that of the core structure,

practically no part of the flux returns by this path.

In accordance with my present invention, the armature 25 is constantly biased to the position in which the core pins 28 engage the pole piece 8 by means of the contact mechanism of the relay, which contact mechanism I will now describe. Referring now also to Fig. 3, this contact mechanism, in the particular embodiment of my invention illustrated in the drawings, comprises two inverted U-shaped supporting brackets 30 and 30 which are fastened to the underside of the top plate 1, adjacent the opposite sides of the top plate, by means of terminal posts 31 and 31, respectively. A flexible strip 33 is secured at one end to the depending leg 34. of the bracket 30 and the other end of this strip is secured to a contact finger t2 intermediate the ends of the contact finger. The strip 33 at the end which is attached to the leg 34 of the bracket 30, is spaced from the bracket by a spacing member 36? having a rounded edge 37% and the finger 32 extends parallel to the strip 33 on the side of the strip opposite to this spacing member to a point opposite the rounded edge 3'7 in such a manner that if the end of the finger is moved in a manner to deflect the strip, the flexingof the strip will occur adjacent the rounded edge of the spacing member and the flexed portion willbe in the form of a gradual curve. The finger 32? extends horizontally toward the armature 25 in a plane substantially parallel to the plane of the armature and cooperates at its free end with the left-hand side, 'as viewed in Fig. l, of an insulating plate which is secured to the upper end of the armature, and which is best seen in Fig. 3. A compressed coil spring 38 is interposed between the depending leg 39 of the bracket 30 and the contact finger 32 and this spring engages the finger at a point between the rounded edge 3'7 of the spacing member 36 and the point where the strip 33 is'secured tothe finger in such manner that the armature 25 is biased by the spring, through the medium of the finger, to the position shown. The spring 38 is held in place between the leg 39 of the bracket and the finger 32 by means of suitable spring supports 40 and ll riveted, respectively, to the leg 39 and to the finger, and fitting inside of the opposite ends of the spring. Contact buttons 42* and 43 are attached to the finger 32 on opposite sides of the finger, and these contact buttons I cooperate respectively with similar contact buttons 44 and 45 secured to front and back contact springs 46 and 47 to close aback contact B --44 or a front contact 43 45 according as the armature 25 occupies the position in which the core pin 28 engages the pole piece 8 or the position in which the core pin 28 engages the pole piece 8 The front and back contact springs 46 and 47* are secured to the top plate 1 by means of terminal posts 48 and 49 and are provided with suitable stops 50 and 51 to accurately position these springs when the springs are not being engaged by the contact buttons 42 and i3 attached tothe finger 32 A contact finger 32 is attached to the bracket 30 in the same manner that the finger 32 is attached to the bracket 30 and this finger is biased into engagement with the insulating platev 35 carried by the armature and cooperates with front and back contacts in the same manner that the finger 32 is biased into engagementwith the insulating plate 35 and cooperates with'front and back contacts. I

The operation of the relay as a whole is a'sfollows: When the winding 27 is deenergized, the armature is held in the position shown, by the contact mechanism of the relay and also by a small force due to the pull which is exerted on the armature by thepermanent magnet flux and, under these conditions, the back contacts 42 -l4 and 42 -4eP are both closed, while the front contacts 43 5= and 43 45 are both open. jWhen,

pole piece 8 and attracted toward the pole'piece 8 thus causing the armature to move from the 1 position shown to the position in which the core pin 23 engages the polejpiece 8 and, under these conditions, the back contacts 4.2= 4=4= and 4.2 44 become openediand the front contacts ift -45 and 43 -45 become closed. "It willbe obvious, of course, that when the armature is once moved from the position shown to its otherposition as just described, it will remain in its other position until the winding}? again becomes deenergized, at which time the armaturewill return to the position shown due to the bias of the contact mechanism. If current having a polarity opposite to that indicated by the marking on the top plate of the relay should be supplied to the relay for any reason, the armature will remain in the position shownbecause the armature will then be attractedto the pole pieced and repelled from the pole piece 8*.

One advantage of a relay constructed in the 'manner described is that since the armature is freely mounted and is of relatively light weight,

it is capable of vibrating at relatively high speeds.

Another advantage of a relay constructed in i. e manner described is that there are no trunnions or the like to wear, thus insuring a long life without change in contact adjustment or operating characteristics of the relay.

Another advantage of a relay constructed in the manner described is that the relay will satisfactorily operate contacts capable of carrying atively large currents in response to a relatively small power input.

further advantage of a relay constructed in the manner described is that when the relay is used as a track relay in railway signaling systems, if the polarities of adjacent track sections are reversed or staggered, the breaking down of the insulating joints between the sections will not cause improper operation of the relay.

A still further advantage of a relay constructed in the manner described is that the biasing force which makes possible the selective operation of the relay just pointed out is provided by the contact mechanism, thus decreasing the number of parts required to a minimum.

Although I have herein shown and described only one form of relay embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A relay comprising magnetizable bars provided with pole pieces having confronting vertically disposed pole faces, magnetizable members -clamped between said magnetizable bars below said pole pieces but spaced from said bars by fixed air gaps, said magnetizable members being constructed to form a channel directly below the air gap between said pole pieces, a magnetizable armature disposed between said pole pieces and supported 'at its lower end in said channel in such-manner that said armature is free to pivot about its lower end as a fulcrum, means cooperating with said armature to limit vertical displacement and lateral displacement of said armature'in said channel, a permanent magnet connected with said bars opposite said pole pieces to polarize said armature, a winding surrounding said armature, and contact mechanism controlled by said armature and acting to bias said armature to the position in which it engages one of said pole pieces, whereby said relay will respond to current of one polarity only.

2. An electrical relay comprising two magnetizable bars provided at one end with pole pieces havingconfronting pole faces, two magnetizable blocks disposed between the other ends of said bars and each separated from the adjacent bar by a non-magnetic shim, three magnetizable plates clamped between said blocks, the middle plate having its upper end disposed below the upper ends of the two adjacent plates, an armature extending downwardly between said pole pieces and resting at its lower end on the upper end of said middle plate in such manner that said armature is free to vibrate between said pole pieces about its lower end as a fulcrum, said 'armature being provided adjacent its lower end with two oppositely disposed recesses, two fingers formed on the upper end of one of said 'plates other than said middle plate and extending loosely through the recesses in said armature in a manner to prevent displacement of said armature, whereby said armature is pivotally supported without trunnions, a winding surrounding said armature between said pole pieces and the lower end of said armature, and a permanent magnet connected with said bars opposite said pole pieces to polarize said armature.

3. An electrical relay comprising two magnetizable bars provided at one end with pole pieces having confronting pole faces, two magnetizable blocks disposed between the other ends of said bars and each separated from the adjacent bar by a non-magnetic shim, three reagnetizable plates clamped between said blocks, the P51;

middle plate having its upper end disposed below the upper ends of the two adjacent plates, an armature extending downwardly between said pole pieces and resting at its lower end on the upper end of said middle plate in such manner that said armature is free to vibrate between said pole pieces about its lower end as a fulcrum, said armature being provided adjacent its lower end with two oppositely disposed recesses, two fingers formed on the upper end of one of said plates end of said armature, a permanent magnet connected with said bars opposite said pole pieces to polarize said armature, and contact mechanism controlled by said armature and acting to bias said armature to the position in which it engages one of said pole pieces, whereby said relay will respond to current of one polarity only.

4. A relay comprising a top plate of insulating material, a U-shaped non-magnetic bracket secured to the underside of said top plate, two magnetizable bars secured to .the two legs of said bracket in vertical positions, two adjustable pole pieces having vertically disposed confronting pole pieces secured to the upper ends of said bars, two magnetizable blocks secured to the web of said bracket between the lower ends of said bars in spaced relation to each other and to said bars, a non-magnetic bolt extendingthrough said bars and said blocks, two non-magnetic shims one mounted on said bolt between each block and the adjacent bar, three magnetic plates mountedon said bolt between said blocks, the middle plate having its upper edge disposed below the upper magnetizablebars provided with confronting pole pieces, a. magnetiz able member disposed between fsaidbarsandspa'ced therefrom by fixed air gaps, saidma'gnetizable memberbeing provided with a edges of the other two plates to form a channel and one of said two plates having two spaced fingers which extend across the top of said channel, a magnetizable armature extending downwardly between said pole pieces and pivotally supported at its lower end within said channel in such manner that said armature is free to Vibrate between said pole pieces, said armature being provided in its opposite edges with notches which loosely receive said fingers, whereby said armature is pivotally supported withouttrunnions, a winding surrounding said armaturebetween said pole pieces and said blocks, a. permanent magnet connected with said bars opposite said. pole pieces to polarize said armature, an insulating plate secured to the upper end of said armature, an inverted U-shaped bracket secured to the .underside of said top plate, a flexible strip. secured at one end to one of thedepending legs of said inverted U-shaped bracket but spaced from such one leg by a spacing block having one edge rounded, a contact finger secured intermediate its ends to said strip on the side of said strip opposite to said spacing block and having its one end extending parallel to said strip to a point opposite the rounded edge of said spacing block and its other end extending toward said armature and cooperating with said insulating plate, a compressed spring interposed between the other depending leg of said inverted U-shaped bracket and said finger and engaging said .finger at a point between the rounded edge ofsaid spacing block and the point where said finger is secured to said strip in such manner that said armature is biased by said spring through the medium of said finger to the position in which the armature engages one of said pole pieces, and front and back contact springs secured to said top plate and cooperating with said contact finger to close a back or a front contact according as said armature occupies the position in which it engages said one pole piece or the position in which it engages the other pole piece.

armature between said pole pieces and the lower 5. Contact mechanism for a high speed relay comprising a fixed U-shaped bracket, a flexible strip secured at one end to one leg of said bracket but spaced from said one leg by a spacing block having a rounded edge, a contact finger secured intermediate its ends to the free end of said strip onthe opposite side of said strip from said spacing block and having its one end extending parallel to said strip to a point opposite the rounded edge of said spacing block, a compressed coil spring interposed between the other depending leg of said bracket and said finger and engaging said finger at a point between the rounded edge of said spacing block-and the point where said finger is secured to said strip, whereby said finger vis biased to one position bysaid spring, and front and back contact springs cooperating with said contact finger adjacent its free end to closea back or a front contact according as the free end of said finger occupies the position to which it is biased by said spring oris moved a predetermined distance away from this position in a direction "to cause additional compression of said spring.

6. A relayhaving, in combination, a pair of channel on the side facing said pole pieces, a

magnetizable armature disposed between said "pole pieces and fastened at one end in said channel in such manner that said armature is free to pivotfl, about'saidj one end as an axis, means for preventing displacement of said armature out of saidchannel, a winding surrounding said arrnat le; a permanent magnet connected with said two; bars for polarizing said relay. andjcontact mechanism controlled by said armature and acting'tlobiasthe' armature to the position in which it engages one of said pole pieces whereby said relay will respond to current of only one polarity in said winding.

7. An electrical relay having, in combination, two ,magnetizable bars provided with confronting a winding surrounding said armature, a permanent magnet connected with said two bars to polarize said relay, and contact mechanism controlled by said armature and acting to bias the armature to the position in which it engages one of said pole pieces, whereby said relay will respond to current of only one polarity in said winding.

HERMAN G. BLOSSER. 

